The long-awaited announcement will further shake up the turbulent political campaign and threaten Benjamin Netanyahu's lengthy tenure at the top of Israeli politics.

Benjamin Netanyahu has been prime minister of Israel for a total of around 13 years.

Jerusalem:

Israel's attorney general announced Thursday he intended to indict Prime Minister Benjamin Netanyahu on charges of bribery, fraud and breach of trust in a decision just weeks ahead of April elections.

The long-awaited announcement will further shake up the turbulent political campaign and threaten Netanyahu's lengthy tenure at the top of Israeli politics.

Attorney General Avichai Mandelblit said in a statement that he intended to charge the premier pending a hearing, where Netanyahu would be given a chance to defend himself before charges are filed.

The announcement comes ahead of April 9 elections in which Netanyahu is facing a tough challenge from a centrist political alliance headed by a respected former military chief of staff, Benny Gantz.

A couple of hours after the announcement, the prime minister dismissed the allegations as a "witch hunt" meant to topple him in a televised speech from his official residence, a campaign banner reading "Netanyahu Strong Right" behind him.

With his opponents calling for him to resign, he said he planned on being prime minister for a long time to come despite the allegations.

"The left knows it cannot beat us at the polling booth, so for the past three years they have been carrying out an unprecedented witch hunt which has one aim: to topple the right-wing government which I lead," he said.

"The main thing was to influence the elections, even if we know that this house of cards will completely collapse after the elections."

'The Nation's Shame'

Netanyahu has been prime minister for a total of around 13 years and he would be on track to surpass founding father David Ben-Gurion as Israel's longest-serving premier should he win in April.

He is not required to step down if indicted, only if convicted with all appeals exhausted.

The Likud had joined a petition filed with the supreme court to stop Mandelblit from announcing his decision before the elections.

The supreme court on Thursday afternoon rejected the petition, paving the way for Mandelblit to proceed with his announcement.

Netanyahu earlier in the day received support from US President Donald Trump, who defended his Israeli ally in remarks after his summit in Hanoi with North Korean leader Kim Jong Un.

"He's tough, smart, and strong. He's very defensive, his military has been built up a lot."

Netanyahu later thanked Trump on Twitter, while also citing his relationships with the US leader and Russian President Vladimir Putin as being good for Israel in his televised statement.

But after Mandelblit's announcement, Netanyahu was facing renewed calls to resign.

Gantz, who spoke in a televised statement after the prime minister, said "Mr. Netanyahu, this country is dear to us. I am sure it is dear to you too."

"I am turning to you this evening to display national responsibility and to resign from your post," he said.

Labour party leader Avi Gabbay said "put an end to the nation's shame. Don't wage the battle from the prime minister's residence".

Three Separate Cases

Police have recommended Netanyahu's indictment in three different cases, and he has been questioned by investigators numerous times.

In one case, he is accused of pursuing regulatory benefits allegedly granted to telecommunications firm Bezeq in exchange for positive coverage from a related media company.

The attorney general said he intended to indict Netanyahu, 69, for bribery, fraud and breach of trust in that case.

The case against his wife Sara Netanyahu in that investigation was however dropped.

Another involves Netanyahu allegedly seeking a secret deal with the publisher of Israel's top-selling newspaper Yediot Aharonot to ensure positive coverage in return for pushing forward a law that would have limited the circulation of a rival.

Netanyahu faces fraud and breach of trust charges linked to that investigation.

The third case involves suspicions the premier and his family received luxury gifts such as cigars and champagne from wealthy individuals, including Hollywood producer Arnon Milchan, in exchange for financial or personal favours.

He also faces fraud and breach of trust charges in that case.

The announcement Thursday will give further ammunition to his political opponents.

The agreement to form Gantz's centrist alliance under the name Blue and White -- the colours of the Israeli flag -- had already posed a major challenge to Likud.

Prior to the February 21 unveiling of the alliance, Likud had consistently been comfortably ahead in opinion polls.

Polls since then have shown Gantz's alliance with the most seats, though not nearly enough to win outright and it is unclear if he would be able to assemble enough parties for a coalition.